1. Field of the invention
This invention relates to a toner feeding device for feeding toner to a toner hopper of a developing unit provided in an image forming apparatus such as a copying machine, etc.
2. Description of the Prior Art
Conventionally, such a device as disclosed by, for example, a Japanese Patent Laid Open No. SH0-59-34564 has been publicly known as this kind of toner feeding device.
In the device disclosed by the above official gazette of a Japanese patent, a cartridge which accommodates toner is removably installed at an opening provided at the upper part of the hopper. And the toner accommodated in the cartridge is fed to the hopper through a feeding port installed at the lower part of the cartridge and an accommodating port installed at the opening of the hopper. Furthermore, at this time, a leveling member projected downwards from the opening of the hopper is moved in the same direction as the movemental direction of a shutter in line with opening movements of the shutter installed at the feeding port of the cartridge, and the toner fed into the hopper is leveled by the leveling member.
After toner is fed into the hopper as shown above, the cartridge is then removed from the upper part of the hopper.
Furthermore, such technologies as disclosed by, for example, Japanese Patent Official Gazettes No. SH0-59-36268, SH0-59-36270 or SH0-62-978 have been proposed at the standpoint of view in which toner may not leak outsides in line with a series of toner feeding work described above.
In these technologies, such arrangements as the cartridge is locked in movement linked with mounting action of cartridge for the hopper or an opening/closing cover installed at the cartridge and the hopper have been provided, thereby causing leakage of toner due to erroneous operation to be prevented.
Actually however, in a conventional toner feeding device so composed of a leveling member as shown above, there is a shortcoming due to which sufficient leveling effect can not be obtained, because the leveling member moves almost in line with the shutter only when opening the shutter, and heap-up of toner which is made in the hopper through dropping from the cartridge is broken down and leveled by the leveling member.
Especially, it is remarkable, for example, in the case that a lump of a heap of toner drops toward the hopper from the cartridge with some delay of time after the shutter is opened and the leveling member finishes its action.
In the technologies disclosed by each of the above official gazettes which have been proposed for the purpose of preventing leakage of toner toward outside on the occasion of a series of toner feeding work, a lock mechanism and an interlock mechanism are to be installed, respectively, and the construction thereof will be complicated and complex, along with a problem that the production cost thereof will become high.